1. Field of the Invention
The present invention relates to straddle-type vehicles including a link mechanism that connects the left and right front wheels with the body frame.
2. Description of the Related Art
As disclosed in WO 2007/127783, three-wheeled cycles including left and right front wheels connected with the body frame via a link mechanism are known. The link mechanism includes left and right upright rods located to the left and right with respect to the vehicle, a pair of upper suspension arms that connect the left and right upright rods with the body frame, and a pair of lower suspension arms that connect the left and right upright rods with the body frame at a location lower than the upper suspension arms. The link mechanism is generally in the shape of a rectangle, as viewed from the front of the vehicle, and includes the left and right upright rods, the upper suspension arms, and the lower suspension arms, and thus has a so-called double wishbone construction.
In the link mechanism, the upright rods and upper suspension arms are rotatably connected, and the upper suspension arms and vehicle frame are rotatably connected. Further, in the link mechanism, the upright rods and lower suspension arms are rotatably connected, and the lower suspension arms and vehicle frame are rotatably connected. That is, the link mechanism may be deformed depending on the up and down movements of the left and right front wheels, and may also be deformed as the vehicle leans.
WO 2007/127783 discloses a suspension assembly that connects a pair of upper suspension arms above the vehicle frame. This suspension assembly damps vibrations received by the left and right front wheels from the road surface.
After extensive research efforts, the present inventors discovered that some travel conditions may cause vibrations that cannot be damped by a suspension assembly as disclosed in WO 2007/127783. Such vibrations may occur in the left and/or right front wheels when the vehicle leans and turns, for example.
If such vibrations that cannot be damped by the suspension assembly occur while the vehicle is traveling, the travel feel of the vehicle significantly deteriorates.